When a tooth substance in an oral cavity is partially removed because of caries or the like, a treatment in which an original tooth crown morphology is restored using a variety of materials is commonly performed to recover the lost tooth substance aesthetically, functionally, and morphologically. Methods to restore a tooth crown morphology are roughly divided into two types according to the operator. A first type of the methods is performed by a dentist at a dental clinic. The dentist removes a portion of the tooth substance with a disease, and thereafter repairs a tooth crown morphology using a photocurable resin. Another type of the methods is performed by a dental technician at a dental laboratory. In this method, a portion of the tooth substance with a disease is removed at a dental clinic, and thereafter an impression of the portion is taken in the oral cavity to obtain a concave mold. Information on the obtained concave mold is sent to the dental laboratory, and the dental technician fabricates a dental prosthetic restoration based on the information. The treatment method is selected as appropriate by the dentist. In general, if the amount of the removed tooth substance is large and the morphology to be restored is complicated, such as a case where the tooth substance is removed from the entire tooth crown portion or a large number of teeth, the treatment in which a prosthetic restoration fabricated by the dental technician is used is selected.
Various materials are used for the dental prosthetic restoration fabricated by the dental technician. Examples of the material include inorganic materials such as zirconia and porcelain, metal, and photocurable resins. The material is selected according to the medical policy or an aesthetic request from the patient. Prosthetic restorations fabricated using inorganic materials such as zirconia and porcelain are highly aesthetic and functional compared to prosthetic restorations fabricated using metal or photocurable resins. For prosthetic restorations fabricated using metal or photocurable resins, in general, metal is used for portions for which the patient does not make a strict aesthetic request such as posterior teeth, and photocurable resins in a tooth crown color are used for portions for which the patient makes a strict aesthetic request such as anterior teeth.
To fabricate a prosthetic restoration using a photocurable resin, the dental technician builds up the photocurable resin on a metal frame serving as a base using a dedicated instrument. A tooth crown morphology and an occlusal morphology similar to those of the natural teeth are significantly complicated, and thus require much expertise and high technical capabilities to be fabricated by the build-up method, and take a long time to be fabricated.
Therefore, there is also used a method in which a dentist or a dental technician makes a concave mold inside or outside an oral cavity using a silicone impression material for bite registration or for indirect bonding and thereafter a tooth crown morphology or an occlusal morphology is restored using a photocurable resin. Examples of the silicone impression material for bite registration or for indirect bonding according to the related art include the following.
JP05-194860A discloses a composition for bite registration containing a highly dispersible filler subjected to a hydrophobizing treatment, short-chain organopolysiloxane having two or more vinyl groups in a molecule, a short-chain QM resin having some vinyl groups, organopolysiloxane having two or more vinyl groups in a molecule, organohydrogenpolysiloxane serving as a cross-linking agent, a catalyst, and a dye. The composition expresses high optical transparency, tearing strength, and rubber hardness after being cured.
JP09-002916A discloses a composition containing: polyorganosiloxane containing 5 to 60% by weight of substantially straight-chain polydiorganosiloxane with an average degree of polymerization of 3000 to 20000, 10 to 40% by weight of branched polyorganosiloxane or cyclic polyorganosiloxane including a branch, and the remaining percentage of straight-chain polydiorganosiloxane with an average degree of polymerization of 5 to 1000, the polyorganosiloxane having two or more vinyl groups bonded to a silicon atom in a molecule; polyorganosiloxane having three or more hydrogen atoms bonded to a silicon atom in a molecule; and a platinum-based compound. The composition provides good mixability and extrudability with its paste hardly dripping before being cured, and keeps high optical transparency after being cured.